In many wireless devices, closely located transmitters and receivers operate simultaneously in slightly separate frequency bands or in the same frequency band/channel. For example, in multi-band frequency division duplexing (FDD) transceivers, a transmitter in the transceiver operates in different, but possibly close frequency band to a receiver in the transmitter. Interference from the transmit frequency can affect the performance of the receiver even though it is operating at a different frequency band. As the frequencies of the transmitter and receiver get closer together, this problem can get worse.
As another example, in full-duplex wireless transceivers, the transmitter and the receiver of the transceiver transmit and receive on the same frequencies at the same time, but utilize self-interference cancellation to enable communication.
Existing techniques for cancelling interference between closely operating transmitters and receivers have many deficiencies.
Accordingly, new circuits and methods for transceiver self-interference cancellers are desirable.